Everybody’s been asking, ‘Who is Robert Smith?’ He virtually became an overnight success once the donor list was revealed for Smithsonian’s new museum, The National Museum of African American History and Culture.

Though unknown to the world at large, he was ‘The Man’ that many pointed to when the Smithsonian was looking for significant donations.

“We kept wondering, ‘Who is this Robert Smith?’ ” said Adrienne Brooks, director of development for the museum. Meeting Smith became a priority, said Lonnie G. Bunch III, the museum’s founding director. “We wanted to meet him. And soon,” Bunch said, laughing. According to a Washington Post article.

Billionaire philanthropist Robert Smith is the second-highest private donor — at $20 million — to the new National Museum of African American History and Culture. Oprah Winfrey beat him by $1 million. (Ricky Carioti/The Washington Post)

The private-equity financier was the museum’s second-biggest private donor, with a $20 million gift. Oprah Winfrey was No. 1, with $21 million.

Smith has built a fortune that’s made him one of the nation’s richest men — worth $2.5 billion, according to Forbes — but until now he has kept his work and philanthropy relatively quiet.

Even the website of his company, Vista Equity Partners, does not have a picture of him. Better, he had thought, that investors and executives know him first by his abilities. If they saw only the caramel skin of an African American, he might lose out on opportunities.

As Vista’s chairman and chief executive, he is in the business of buying, growing and selling off software companies. Vista’s portfolio has 35 companies with $26 billion in assets under management. He is the majority shareholder of Vista’s management company.

Beyond Wall Street and Silicon Valley, Smith long enjoyed moving in relative obscurity. That changed last fall when Forbes magazine put him on its cover, with an article for which he declined to be interviewed.